Digging device



p 17, 1953' H. w. HENDERSON 3,103,982

DIGGING DEVICE Filed March 26, 1962 so? ,f /4

INVENTOR Harvey W Henderson A TTYS.

United States Patent 3,103,982 DlGGiNG DEVICE Harvey W. Henderson, Pacific City, Oreg. Filed Mar. 26, 1962, Ser. No. 182,407 7 Claims. (Cl. 175-403) This invention relates to digging devices, and more particularly to digging devices comp-rising an elongated hollow digging member having an open bottom end and adapted to be forced into the ground, and including means whereby the top end thereof may be closed off, so that when the device is withdrawn resulting suction functions to hold a core of material within the device permitting its withdrawal with the device.

Exemplary of such digging devices, and the subject of a preferred and specific embodiment of this invention, are the so-called clam guns used in clam digging. Such clam guns are quite prevalent on the beaches of the Northwest, and are used in digging for razor clams which otherwise elude capture because of their ability to burrow rapidly in the sand. A clam gun nonmally oomprises a hollow tube that is thrust into the sand with the walls of the tube surrounding a clam when finally positioned. With the tube in place and about a clam, the walls prevent a clam from digging laterally and escaping, and if the clam gun is pushed into the sand rapidly, a clam cannot escape around the base of the tube. Upon closing a vent provided in the top of the gun, and withdrawing the gun, a core of sand and the clam may be removed, and the clam may then be freed by opening the vent and shaking the gun so that material inside falls out the bottom of the tube.

In such devices, as may be seen from the above, it is important that the top end of the tube be closable, in order that a suction or subatmospheric pressure may be produced within the top of the tube upon its withdrawal, enabling sand or other material to be held in place and be lifted together with the tube. A factor that has not as yet received much consideration is that withthe tube fully loaded wih sand, withdrawal from the ground is difiicult because of suction or su-batmospheric pressure produced at the base of the tube by the displacement of the tube and its contents upwardly. Such a tube in a clam gun may have a relatively large cross-sectional area (normally the tube may have a diameter of six inches or so), and upon displacing the tube upwardly, subatmospheric pressure acting upon the entire cross-sectional area of the tube must be overcome. The problem, of course, is complicated by the fact that sand containing clams frequently is wet, and the production of more nearly perfect vacuums at the base of the tube results than were the sand dry.

Generally, it is an object of this invention to provide "an improved digging device, such as a clam gun, where means is provided for breaking the suction produced at the base of the device, when the same is withdrawn with a core of material therein.

More specifically, this invention contemplates such a digging device, that includes means defining an elongated pass-age extending from adjacent the top end to -adjacent the bottom end of the tube therein, such passage constituting a vent passage operable to break suction at the base of the device.

In a preferred embodiment of the invention, an elongated, relatively small diameter conduit is provided, and this is secured to the side wall of a larger, digging tube, with such positioned on the inside of the digging tube. The pipe has a flattened, bottom end, secured to the side wall of the digging tube. Openings communicating with the interior of the pipe adjacent its bottom end are in the form of slots cut into the side of the pipe adjacent its bottom end. The top end of the pipe is open and exice posed. By flattening the bottom end of the pipe and thus closing it off, material is prevented from being forced into the pipe or conduit when the clam gun is thrust downwardly into the sand. The openings adjacent the bottom end of the pipe tend to remain clear, enabling atmospheric pressure to be reached at the base of the digging device upon its withdrawal. The construction leaves no protwberances on the' outside of the clam gun;

The pipe, since it is of small diameter, does not reduce significantly the size of the core of sand that can be picked up by the gun, By leaving the top end of the pipe open and exposed, should sand inadvertently find its way into the interior of the pipe, the same may be emptied easily by inverting the clam-gun and shaking it slightly.

A more specific object,therefore, is to provide a digging device with a'vent passage in the term of a pipe secured to the wall of'a digging tube in the device, more specifically a pipe disposed inside the digging tube.

Another object is to provide such a device, wherein the base of the pipe defining a vent passage therein is closed, preferably by flattening it against the side of the digging tube, and openings in the-side of the pipe adjacent its base provide openings communicating with the interior of the pipe.

A still further object is to provide such a device V FIG. 2 is a top-view, looking down at the top of the clam gun illustrated in FIG. 1;

FIG.3 is a cross-sectional view, taken generally along the lines of 3-3 in FIG. 2; and

FIG. 4 is a cross-sectional view, taken generally along the line 44 in FIG.-3,-and on a slightly enlarged scale,

illustrating details of a vent-pipe in the construction.

Referring now to the drawings, a clam gun is indicated generally at 10. As shown, the device comprises an elongated hollow digging member, or tube, indicated at 12, 1 and secured to the sideof tube 12 adjacent its top end,

handles 14. These are provided to iacilitate the insertion of the clam gun into the ground, and its retraction. I

The handles normally extend outwardly from approximately diametrically opposite sides of tube 12.

Tube 12 has an open bottom end 16. Preferably the wall of tube 12 at end 16 is beveled, as at is. The

sharpened edge resulting provides a cutting edge for the clam gun when the same is thrust into the sand.

While bottom end 16 of tube '12 is open, the top end is closed as by a'wall 20, save for'an aperture or vent 22 in wall 20. Vent 22 opens the inside of tube 12 to the atmosphere adjacent the top of the tube. Ordinarily, the vent is located substantially centrally in wall 20, in a position where a user may place a thumb easily thereover to close it off, with the remainder of his hands in a position grippinghandles 14. The vent and wall 20 constitute arneans adjustably closing olf the top of the tube.

Considering now the means provided for venting the base of the clam gun, and breaking suction otherwise resulting at the base of the gun upon its withdrawal, at

24 there isindicated an elongated conduit or pipe fastened to the wall of tube 12. The pipe extends along the length of the tube on the inside of the tube. The pipe may be fastened in place in any suitable manner, as by welding.

Pipe 24 has openings adjacent top and bottom ends communicating with the interior thereof. Thus, the top end of pipe 24 may abut the underside of wall 20, and be fastened in position against the underside of wall 20. The top end is open, and communicates with a bore or aperture 26 provided directly thereover in wall 20. In this manner the open top end is exposed to the outside of the clam gun. The open top end of the pipe and bore 26 provide an opening for the top of the pipe that is axially aligned with the pipe.

Considering the bottom end of pipe 24, this preferably is flattened, as at 28 (see FIG. 4), to close it oif. By flattening the bottom end, not only is the pipe closed ofi, but a tapered outline is produced, which decreases the resistance the pipe offers when the gun is thrust downwardly into the sand. Openings in pipe 24 adjacent its end are provided by slots 30 extending into the sides of the pipe. In the embodiment illustrated, there are six of such slots. The slots occupy planes, as indicated by the line 30a, that define acute angles relative to the longitudinal axis of pipe 24.

It is preferable not to have the bottom end of pipe 24 open in the same manner as the top end of the pipe, since this would enable sand easily to travel up into the pipe when the gun was pushed down into the sand. Such sand would close it oh, and prevent proper venting action by pipe 24. By providing the side openings illustrated, clogging of pipe 24 with sand is inhibited.

Explaining the use of the clam gun, when the same is thrust in the sand, vent 22 is left open (to allow air to escape from the interior of tube 12 as sand moves up into the tube). On the gun being finally positioned, as shown in FIG. 1, the user places his finger over vent 22 to close it off. If the gun is then pulled upwardly to retract it, due to the fact that air now is prevented from entering tube 12 at the top of the gun, a core-of sand is held by atmospheric pressure within the gun, and such core is removed simultaneously with removal of the clam gun. Pipe 24 provides a passage connected at its upper end with the atmosphere that extends to the base of the tube and opens into the sand adjacent the base of the tube. Because of this passage, the suction otherwise resulting on withdrawal of the gun is broken, with the result that a force need be exerted that is only sufiicient to lift the weight of the device and the sand therein.

If desired, and further to assure that sand does not enter into the vent pipe during positioning of the clam gun, the user may place his thumb over bore 26 when the gun is pressed into the ground. This captures air within the pipe.

In the event that some sand should work its Way into the vent pipe, the same is easily removed by inverting the clam gun, and shaking it, with sand and other matter falling from the open top end of the vent pipe and out of bore 26. v

The diameter of the vent pipe is minor compared with the diameter of tube 12. Thus, it has no significant effect on the size of the core dug by the gun. With the pipe inside tube 12, the same is protected along its length by the wall of tube 12.

I claim:

1. In a digging device, an elongated digging member comprising an elongated hollow casing and a wall extending over the top end of said casing closing off the top end, said casing having an open bottom end, a manually closable vent connecting with the inside of said casing adjacent the top end thereof, means defining a passage extending between the ends of the digging member, and openings adjacent the top and bottom ends of the digging member connecting said passage with the atmosphere, said openings with the digging member in the ground enabling the passage of air from the top of the digging member and through the passage to the bottom of the digging member thus to break suction at the base of the device upon retraction of the device from the ground.

2. The digging device of claim 1, wherein said passage has a closed bottom end, and the opening for said passage adjacent the bottom end thereof communicates with said passage from the side of said passage 3. In a clam gun, an elongated hollow digging tube having an open bottom end, a wall extending over the top end of said tube closing it off, a manually closable vent extending through said wall and connecting with the inside of the tube adjacent the top end thereof, a conduit fastened to said tube extending between the top and bottom ends of said tube and defining an elongated passage extending the length of said tube, and openings adjacent the top and bottom ends of the conduit, respec tively, connecting said passage with the atmosphere, the opening adjacent the bottom end of said conduit communicating with said passage from the side of said conduit.

4. The device of claim 3, wherein said conduit is substantially straight, and the opening adjacent the top end of said conduit communicates with said passage from the end of the conduit.

5. In a digging device, an elongated hollow digging tube having an open bottom end, a wall closing off the top end of said tube, a manually closable vent extending through said wall and connecting with the inside of said tube adjacent the top end thereof, and a conduit for breaking suction at the bottom of the device extending along the inside of the tube along the length thereof, said conduit defining a passage extending from the bottom to the top of the tube, said conduit being fastened to the inner wall of said tube and having a bottom end that is flattened against the side of said tube and closed, slots in the side of said conduit adjacent its bottom end defining openings communicating with the interior of said conduit, and an opening for the conduit communicating with its interior adjacent the top end of the conduit.

6. The device of claim 5, wherein said slots occupy planes disposed at an acute angle relative to the longitudinal axis of said conduit and incline upwardly progressing from the center of said conduit outwardly, and the opening for the conduit adjacent the top end thereof comprises an opening aligned longitudinally with the passage defined by said conduit.

7. In a clam gun, an elongated hollow digging tube having an open bottom end, a wall extending over the top end of said digging tube and closing it off, handle means joined to said digging tube adjacent the top end thereof, a manually closable vent extending through said wall connecting the outside of said tube above said Wall with the inside of the tube, an elongated conduit secured to the wall of said digging tube on the inside thereof and extending between the top and bottom ends of the tube, said conduit defining a passage extending the length of the digging tube, an opening in the wall of said conduit adjacent the bottom end thereof connecting said passage with the inside of said tube, and an opening in the top end of said tube connecting said conduit with the outside of said tube above said wall.

References Cited in the file of this patent UNITED STATES PATENTS 618,422 Leroux Jan. 31, 1899 1,172,139 Jenkins Feb. 15, 916 2,008,523 Thomas July 16, 1935 2,509,883 Rolshausen et al May 30, 1950 2,951,681 Degen Sept. 6, 1960 

7. IN A CLAM GUN, AN ELONGATED HOLLOW DIGGING TUBE HAVING AN OPEN BOTTOM END, A WALL EXTGENDING OVER THE TOP END OF SAID DIGGING TUBE AND CLOSING IT OFF, HANDLE MEANS JOINED TO SAID DIGGING TUBE ADJACENT THE TOP END THEREOF, A MANUALLY CLOSABLE VENT EXTENDING THROUGH SAID WALL CONNECTING THE OUTSIDE OF SAID TUBE ABOVE SAID WALL WITH THE INSIDE OF THE TUBE, AN ELONGATED CONDUIT SECURED TO THE WALL OF SAID DIGGING TUBE ON THE INSIDE THEREOF AND EXTENDING BETWEEN THE TOP AND BOTTOM ENDS OF THE TUBE, SAID CONDUIT DEFINING A PASSAGE EXTENDING THE LENGTH OF THE DIGGING TUBE, AN OPENING IN THE WALL OF SAID CONDUIT ADJACENT THE BOTTOM END THEREOF CONNECTING SAID PASSAGE WITH THE INSIDE OF SAID TUBE, AND AN OPENING IN THE TOP END OF SAID TUBE CONNECTING SAID CONDUIT WITH THE OUTSIDE OF SAID TUBE ABOVE SAID WALL. 